JPH1191238A - Manufacture of material to be recorded for ink jet recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide manufacturing methods for a material to be recorded for ink jet recording having a glass which is similar to a photographic printing paper of photograph, or a material to be recorded for ink jet recording of a high transparency which can be used as an OHP film or the like, and in addition, in details, provide a manufacturing method for a material to be recorded for ink jet recording wherein a cracking of an ink absorbing layer at the time of drying is suppressed in a manufacturing method for a material to be recorded for ink jet recording wherein an ink absorbing layer containing an alumina hydrate is provided on a supporting body. SOLUTION: A coating liquid containing an alumina hydrate is applied on a supporting body, and until the concentration of the coating liquid applied on the supporting body exceeds 25 wt.%, the supporting body is dried under a state wherein air is not substantially applied to the coated surface side, and an ink absorbing layer is formed. As drying methods, a method wherein a drying is performed using a thermal light source, a method wherein a drying is performed by applying hot air to the surface opposite from the coating liquid applied surface, and a method wherein a drying is performed by applying a heating medium to the surface opposite from the coating liquid applied surface or the like are especially preferable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an ink jet recording material used for a printer or a plotter using an ink jet recording system, and particularly to a photographic printing paper for which there is a high demand for color recording. The present invention relates to a method for producing an inkjet recording material having a high gloss, a highly transparent inkjet recording material that can be used as an OHP film, and the like.

[0002]

2. Description of the Related Art In recent years, remarkable progress in ink jet printers and plotters has made it possible to easily obtain full-color and high-definition images. Along with this, development of a recording material for inkjet other than conventional high-quality paper and coated paper for inkjet recording has been eagerly desired.

In the ink jet recording system, fine droplets of ink are caused to fly by various operating principles and adhere to a recording material such as paper to record images, characters, and the like. Inkjet printers and plotters have the features of being excellent in high-speed printing and low noise, having great flexibility in recording patterns, and requiring no development-fixing, and are capable of forming complex images accurately and quickly. It is attracting attention. In particular, as an apparatus for creating a hard copy of image information such as characters and various figures created by a computer, it is rapidly spreading in recent years in various applications. Also, by using a plurality of ink nozzles, it is easy to perform multicolor recording. The color image formed by the multi-color ink jet method can obtain a record comparable to the multi-color printing by the plate making method and the printing by the color photographic method, and in applications where the number of copies is small, It is being widely applied because it is less expensive than printing and photographic techniques.

In recent years, ink jet printers and the like which can output a high-definition image comparable to a silver halide photograph image have been commercially available at low cost. Inkjet recording materials are very inexpensive, while still providing the same quality images as silver halide photographic methods, so users who frequently change display images on signboards or product samples that require large area images Has significant economic benefits for In addition, it is impossible to create an image on a computer and correct the color scheme and layout while looking at the printout, but it was impossible with the conventional silver halide photography method, but such an operation can be easily done with inkjet recording There is also an advantage.

[0005] As fields of application of ink jet printers and plotters, attention has recently been paid particularly to the production of color printing plates in the printing field where image quality close to a photograph is required and the output of design images in the design department. Or an image information created by a computer is recorded on a transparent recording material using an ink jet printer, and is used by an OHP (overhead projector) for a presentation at a meeting or the like.

[0006] With the above-mentioned demands from the field of application of ink-jet printers and plotters and the spread of ink-jet printers and plotters, demands for recording materials have diversified. Recording material with excellent appearance aptitude, OHP
There is a demand for highly transparent recording materials that can be used as films.

As the recording material used in the ink jet recording system, efforts have been made in terms of apparatuses and ink compositions so that ordinary printing or high quality paper for writing or coated paper can be used. However, as the performance of the ink jet recording apparatus has been improved and the use thereof has been expanded, such as higher speed, higher definition, and full color, more advanced characteristics have been required for the recording material. That is, the recording material is required to have a bright and vivid color tone, to be able to absorb ink quickly, and to prevent ink from flowing out or bleeding even when print dots overlap. In particular, in the case of color recording, yellow, magenta,
In addition to monochromatic recording of cyan and black, multicolor recording in which these colors are superimposed is performed, and extremely strict performance is required in order to further increase the ink adhesion amount.

Conventionally, as a recording material for ink jet,
For example, JP-A-55-51583, JP-A-56-157,
57-107879, 57-107880, 59-230787, 62-160277, and 6
2-184879, 62-183382, 64
No. 11877 has proposed a recording material obtained by applying a silicon-containing pigment such as silica to a paper surface together with an aqueous binder. Inorganic pigments such as silica have a large oil absorption, and recording materials containing inorganic pigments such as silica as a main component of the ink absorbing layer generally reach a certain level in terms of ink absorption capacity and absorption speed. There is a disadvantage that the surface gloss of the recording material itself cannot be obtained. It is not preferable to use colloidal silica in place of silica for the purpose of obtaining gloss because the ink absorbency deteriorates as described in JP-A-56-157. As an inkjet recording material having a glossy surface, a cast coated paper obtained by performing a cast finish while the coating layer is in a wet state is disclosed in JP-A-6-320857.
Although the surface gloss is extremely low as compared with silver halide photographs, the texture of silver halide photographs cannot be obtained.

On the other hand, as an ink jet recording material having improved transparency and glossiness, a material having an ink absorbing layer made of a resin on a support has been proposed. Examples of resins used in such applications include, for example, JP-A-57-3
Nos. 8185 and 62-184879, polyvinylpyrrolidone, vinylpyrrolidone-vinyl acetate copolymer, JP-A-60-168651, and JP-A-60-168651
Nos. 0-171143 and 61-134290, resin compositions mainly comprising polyvinyl alcohol, and vinyl alcohol and olefin or styrene and maleic anhydride as described in JP-A-60-234879. A crosslinked product of polyethylene oxide and isocyanate as shown in JP-A-61-74879, a mixture of carboxymethyl cellulose and polyethylene oxide as shown in JP-A-61-181679, JP-A-61-13237
Patent No. 7: Polymer obtained by grafting methacrylamide to polyvinyl alcohol
An acrylic polymer having a carboxyl group as described in JP 220383, a polyvinyl acetal polymer as described in JP-A-4-214382, and the like, as described in JP-A-4-282282 and JP-A-4-285650. Various ink absorbing polymers such as various crosslinkable acrylic polymers have been proposed. In addition, Japanese Unexamined Patent Application Publication No.
JP-A-282282 and JP-A-4-285650 propose a recording material in which a polymer matrix composed of a crosslinkable polymer and an absorbent polymer are mixed, but an ink absorbing layer made of a resin is made of silica. It has a drawback that the absorption rate is lower than that of the ink absorption layer composed of pigment fine particles.

As an ink-jet recording material having a high ink absorption speed and improved transparency and gloss, an ink-jet recording material using alumina hydrate has recently been proposed. No. 60-232990, 6
JP-A-245588, JP-B-3-24906, JP-A-2-276670, and 3-215082
Nos. 4-37576 and 4-67986, 5-1
No. 6517, No. 5-24335, No. 5-32037
Nos. 5-50739, 5-286228, and 5
Nos. -301441, 6-48016 and 6-558
No. 29, No. 6-183126, No. 6-184954
Nos. 6-199034, 6-199035, 6-218324, 6-255235, 6-26
No. 2844, No. 6-270530, No. 6-28629
No. 7, No. 6-297831, No. 6-297832,
6-316145, 7-68919, 7-6
No. 8920, No. 7-76161, No. 7-76162
And JP-A-7-82694, JP-A-7-89221, and the like, disclose a recording material for ink jet recording in which fine alumina sol is coated on the surface of a support together with a water-soluble binder. However, as described in JP-A-5-24335, the ink absorption layer made of alumina hydrate has insufficient ink absorption capacity unless the coating amount is about 20 g / m ² or more. Although film coating is necessary, when the thick film is coated, cracks are very likely to occur in the ink absorbing layer during drying, and it is necessary to suppress the occurrence of cracks during drying.

As a method for suppressing cracking of a coating film during coating and drying of an ink absorbing layer composed of alumina hydrate, polyvinyl alcohol is used as a binder as described in JP-A-7-76161. A method has been proposed in which polyvinyl alcohol as a binder is gelled with boric acid or borate to improve the strength of a coating film, thereby suppressing cracking. However,
The gelation reaction between polyvinyl alcohol and boric acid and borate is very fast, and the change in viscosity of the coating solution over time cannot be avoided, resulting in poor coating stability. In addition, the gelled product may cause streak, and may cause deterioration of surface quality. JP-A-6-218324 proposes a method in which a coating solution comprising alumina hydrate is applied on a support, and ammonia gas is sprayed before removing the solvent to cause gelation. However, ammonia gas is not only highly corrosive but also explosive and dangerous. In addition, it is necessary to recover excess ammonia gas, which is not desirable in terms of simplicity of operation and equipment. As a method for solving the above-mentioned problem, Japanese Patent Application Laid-Open No. 7-89221 proposes a recording material for ink jet having an ink absorbing layer composed of alumina hydrate and gelatin. This method utilizes the property that a gelatin solution dissolved in warm water gels at a low temperature. However, in this method, when the drying temperature is increased, gelatin is re-solubilized, so that it is necessary to dry at a low temperature at a reduced coating speed.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a recording material used in a printer or a plotter utilizing an ink jet recording system. It is an object of the present invention to provide a method for producing an ink jet recording material having a photographic paper-like gloss and a highly transparent ink jet recording material that can be used as an OHP film.

More specifically, in a method for manufacturing an ink jet recording material having an ink absorbing layer containing alumina hydrate provided on a support, the ink jet recording material in which cracking of the ink absorbing layer during drying is suppressed. Is to provide a method of manufacturing the same.

[0014]

The object of the present invention has been attained by the following means. That is, in the method for producing an ink jet recording material provided with an ink absorbing layer containing alumina hydrate on a support, a coating liquid containing alumina hydrate is applied on the support, The problem could be solved by forming the ink absorbing layer by drying in a substantially airless state until the concentration of the coating liquid applied on the substrate exceeded 25% by weight.

In the present invention, drying in a state where the air is not substantially applied means that the air is dried without directly blowing the air to the surface of the support coated with the coating liquid.

On the other hand, in the present invention, drying in a state where air is blown means that wind is generated from a nozzle using power,
This refers to drying by directly blowing air from a nozzle to the side of the support coated with the coating liquid.

As a method of drying in a state where air is not substantially applied, drying by a heat light source such as a far-infrared heater, a method of applying hot air from a side of the support not coated with a coating liquid, a method of drying the support, A method in which a heat medium such as a hot plate or a hot roll is applied to the surface not coated with the coating liquid is preferable,
The present invention is not limited to these.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention provides a method for producing an ink jet recording material having an ink absorbing layer containing alumina hydrate on a support, wherein the ink absorbing layer is made of alumina hydrate. Coating a coating solution containing a substance on a support,
It is formed by drying.

However, it is difficult to increase the concentration of the dispersion of the alumina hydrate in a stable dispersion state, and usually a stable dispersion can be obtained unless it is 20% by weight or less, preferably 15% by weight or less. Absent. In order to obtain a good ink absorption capacity, 20 g / m ² or more as a solid coating amount, preferably requires 30 to 50 g / m ² or more, at least 100 g / m ² or more as a coating solution amount, preferably 150 It is necessary that ３００300 g / m ² can be coated on the support.

When the amount of the coating liquid to be applied is extremely large as described above, if the coating is dried in a wind, a wind ripple or the like is generated on the coating surface, resulting in an uneven coating surface. Also, the wind ripple,
In portions where the coating surface is not uniform, cracks may occur on the coating surface during drying due to different shrinkage during drying.

On the other hand, when drying is performed in a state where the wind is not substantially applied, the generation of wind ripples is suppressed, and as a result, cracks on the coated surface due to shrinkage during drying can be suppressed. However, when the drying is performed in a state where the air is not substantially applied, the drying speed is much slower than when the drying is performed in the state where the air is applied.

As described above, it is difficult to increase the concentration of the dispersion of alumina hydrate in a stable dispersion state, and it is usually not more than 20% by weight, preferably not more than 15% by weight. Can not be obtained. However, if the content exceeds 25% by weight, remarkable thickening or gelation occurs, and even when dried in a wind, there is almost no occurrence of wind ripples that cause cracks.

Therefore, the coating liquid applied on the support is dried in a substantially airless state until the concentration of the coating liquid applied on the support exceeds 25% by weight. If it exceeds 25% by weight, a drying method that emphasizes drying efficiency, such as direct blowing, may be used.

In the present invention, the concentration of the coating liquid indicates the content of alumina hydrate in the coating liquid unless otherwise specified. Alumina hydrate has various forms, but when calculating the coating solution concentration, monohydrate (Al ₂ O _3.
H ₂ 0).

In the present invention, as a method for drying in a state where the air is not substantially applied, as described above, drying by a heat light source such as a far-infrared heater, and starting from the side of the support which is not coated with a coating liquid. Or a method in which a heat medium such as a hot plate or a hot roll is applied to the surface of the support on which the coating liquid is not applied, but the present invention is not limited thereto.

The heat light source refers to a light source that generates heat when emitting light, and examples thereof include a tungsten lamp, a halogen lamp, a xenon lamp, a metal halide lamp, and an infrared lamp. Particularly, a halogen lamp and an infrared lamp are preferably used.

As the alumina hydrate used in the present invention, an alumina hydrate selected from a pseudo-boehmite structure or an amorphous structure is preferable. Particularly preferred because of its large size.

The alumina hydrate is Al ₂ O ₃ .x
It is a general term for substances represented by the chemical formula of H ₂ O, and is expressed as gibbsite, vialite, norstrandite, boehmite, boehmite gel (pseudo-boehmite), diaspore, amorphous alumina gel, etc., depending on the composition and crystal form. You. In addition, since alumina hydrate does not recognize the presence of water molecules by infrared absorption, the expression alumina hydrate is not accurate, but in the present invention, according to custom, the name of alumina hydrate is used. I do.

Alumina hydrate often exists together with a stabilizer (deflocculant) in the form of a dispersion, and is roughly classified into a slurry form and a colloidal form according to the particle size. But the boundaries are not clear. The colloidal alumina hydrate dispersion is often referred to as alumina sol or colloidal alumina, and the X-ray diffraction pattern of the dried product (xerogel) is that of an amorphous or boehmite gel (pseudo-boehmite). Often shown.

The difference between boehmite and pseudo-boehmite is that the hydration number is different, and pseudo-boehmite has a higher hydration number. More specifically, the boehmite crystals are aluminum oxide monohydrate (Al ₂ O ₃ .H ₂ O),
The smaller the particle size, the more the amount of water molecules hydrated on the surface cannot be ignored. Therefore, in the case of colloidal alumina or the like in which microcrystals of boehmite alumina hydrate are dispersed in water, the apparent hydration number increases and is represented by the chemical formula of Al ₂ O ₃ .1 to 1.5 H ₂ O. , May be called pseudo-boehmite.

In the present invention, a gel is a sol (colloidal or slurry-like dispersion) solidified while containing a solvent such as water, and a gel having a small amount of water is distinguished from a xerogel. .

The deflocculant, which is a dispersion stabilizer of alumina hydrate, is an ion for neutralizing charged particles, and is a source of anions because alumina hydrate is positively charged when acidic. Acids such as nitric acid, hydrochloric acid, formic acid, and acetic acid are mainly used as a peptizer for alumina hydrate, but the present invention is not limited to these.

The deflocculation refers to a phenomenon in which particles have a strong repulsive force in a medium and the particles are stably dispersed in the medium.
In order for the particles to have a repulsive force, the particles must be charged and ions having the opposite sign to neutralize the particles must be adsorbed and have an electric double layer. This electric double layer electrostatically repels and prevents the particles from approaching. If the particles are uncharged and no electric double layer forms on the surface, peptization will not occur.

In order for the alumina hydrate to have a sufficient ink absorption capacity, the pore volume of the alumina hydrate should be 0.3-2.
It is preferably in the range of 0 ml / g, especially 0.4 to
It is preferably in the range of 1.0 ml / g. If the pore volume of the ink absorbing layer is large, cracking or powder dropping may occur in the ink absorbing layer, and if it is small, ink absorption tends to be slow. Further, the solvent absorption amount of the ink absorbing layer per unit area is preferably 5 ml / m ² or more, particularly preferably 10 ml / m ² or more. When the amount of solvent absorption per unit area is small, the ink may overflow especially when multicolor printing is performed.

In order for the alumina hydrate to have a sufficient ink absorption rate, the average pore radius of the alumina hydrate must be 1
It is preferably from 20 to 20 nm, particularly preferably from 3 to 10 nm. If the pore radius is too small, it becomes difficult to absorb the ink. On the other hand, if the pore radius is too large, fixation of the dye in the ink will be poor, and image bleeding will occur.

In order for the alumina hydrate to sufficiently absorb and fix the dye in the ink, the BET specific surface area is 70 to 300 m.
It is preferably in the range of ² / g. If the BET specific surface area is too large, the efficiency of fixation of the dye in the ink becomes worse due to the larger pore size distribution, resulting in image bleeding. Conversely, if the BET specific surface area is too small, dispersion of the alumina hydrate becomes difficult.

In order to increase the concentration of the alumina hydrate dispersion, the number of surface hydroxyl groups of the alumina hydrate should be 10 ²⁰ /
g or more. When the number of surface hydroxyl groups is small, alumina hydrate tends to aggregate, and it becomes difficult to increase the concentration of the dispersion.

In the present invention, the alumina hydrate is usually coated on a support together with a water-soluble binder. A plurality of water-soluble binders can be used in combination for the purpose of adjusting the liquid properties of the coating liquid, the viscosity of the coating liquid, the film-forming properties and strength of the ink absorbing layer, and the like. As such a water-soluble binder, completely saponified or partially saponified polyvinyl alcohol is particularly preferable in view of mixing property with alumina hydrate, adjustment of coating solution viscosity, etc., but methyl cellulose, methyl hydroxyethyl cellulose, methyl Cellulosic binders such as hydroxypropylcellulose and hydroxyethylcellulose, starch and modified products thereof, gelatin and modified products thereof, casein, pullulan, gum arabic, karaya gum, albumin, chitosan and other natural polymer resins or derivatives thereof, and cationic modification , Poly (vinyl alcohol) modified products such as silanol modified products, SBR latek, NBR latex, latexes such as methyl methacrylate-butadiene copolymer, ethylene-vinyl acetate copolymer, polyacrylamide, polyvinyl alcohol Vinyl polymers such as Rupiroridon, polyethyleneimine, polypropylene glycol, polyethylene glycol, may be mentioned maleic anhydride or a copolymer thereof, etc., the present invention is not limited thereto.

In order to obtain good liquid properties when the coating liquid is prepared, it is preferable to select a water-soluble binder so that the viscosity of the coating liquid to be prepared is 100 cps or more. In addition, if the viscosity of the coating liquid is too high, coating may be difficult. Therefore, it is preferable to select a water-soluble binder so that the viscosity of the coating liquid is 5000 cps or less.

When the amount of the water-soluble binder used in the present invention is too small, the strength of the ink absorbing layer is weakened. On the contrary, when the amount is too large, the absorption of the ink may be hindered. 5 to 2 for Japanese
It is preferably 0% by weight, particularly preferably 10 to 15% by weight.

In the present invention, the layer constitution of the ink absorbing layer may be a single layer or a laminated layer.

In the case of a laminated structure, all the layers may be layers containing alumina hydrate and a water-soluble binder, or a layer composed of other components and a layer containing alumina hydrate and a water-soluble binder. May be used.

When all the layers are layers containing alumina hydrate and a water-soluble binder, the same layer may be laminated for each layer, or layers having different characteristics may be laminated. For example, in the case of a two-layer configuration, a layer having a large pore diameter is provided in the upper layer for the purpose of increasing the ink absorption rate, and a layer having a small pore diameter is provided in the lower layer to be advantageous in light transmission. A layer structure suitable for the purpose, such as balancing light transmission, can be obtained.

In the case of a laminated structure of a layer composed of other components and a layer containing alumina hydrate and a water-soluble binder, for example, the purpose is to improve scratch resistance, scratch resistance and the like. An ink-permeable protective layer such as colloidal silica can be provided on the layer containing alumina hydrate and a water-soluble binder. Also, for the purpose of increasing the ink absorption capacity, for example, an ink absorption layer made of a water-soluble resin such as polyvinyl alcohol or polyvinylpyrrolidone is provided below the layer containing alumina hydrate and a water-soluble binder,
The layer structure can be adapted to the purpose.

As a raw material of alumina hydrate, Japanese Unexamined Patent Publication No.
Nos. 7-88074 and 62-56321,
No. 275917, No. 6-64918, No. 7-1053
No. 5,7-267633, U.S. Pat.
6,321, Am. Ceramic Soc.
Bull. , 54, 289 (1975) discloses a method of hydrolyzing an aluminum alkoxide.
In this method, very pure alumina hydrate can be obtained.

On the other hand, as a raw material of alumina hydrate, inorganic salts of aluminum as exemplified in JP-A-54-116398, JP-A-55-23034, JP-A-55-27824 and JP-A-56-120508 are used. Or its hydrate is generally used. As these inorganic salts, for example, aluminum chloride, aluminum nitrate,
Examples include inorganic salts such as aluminum sulfate, polyaluminum chloride, ammonium alum, sodium aluminate, potassium aluminate, and aluminum hydroxide, and hydrates of these inorganic salts.

Sodium ions, potassium ions, sulfate ions, and the like contained in the inorganic salt of aluminum inhibit increase in the solid concentration of the dispersion. Therefore, when an inorganic salt or its hydrate is used as a raw material of alumina hydrate, it is necessary to remove these ions.

It is difficult to remove from the alumina hydrate dispersion ions such as sodium ions, potassium ions, sulfate ions and the like that inhibit high concentration (hereinafter simply referred to as inhibitory ions). It is effective to wash the gelled alumina hydrate gelled. However, these inhibitory ions cannot be completely removed by washing with water or a large amount of water is often required to remove them, and gel-like alumina is used by using an aqueous solution containing a volatile basic substance such as ammonia. By washing the hydrate, the inhibitory ions can be more effectively removed.

The volatile basic substance used for washing partially adsorbs to alumina hydrate and cannot be completely removed by washing with water. However, by drying the gel-like alumina hydrate to form a xerogel, volatile basic substances can be effectively reduced. In addition, as a method of obtaining xerogel, there is a method of drying the alumina hydrate dispersion by hot air drying, reduced pressure drying, freeze drying, spray drying, or the like. Note that a dispersion of alumina hydrate can be obtained by redispersing xerogel in water.

The method for producing alumina hydrate is not particularly limited. For example, aluminum sulfate,
Alumina hydrate can be produced by a neutralization reaction between an acidic aluminum salt aqueous solution such as aluminum nitrate and aluminum chloride and a basic aqueous solution such as sodium aluminate, sodium hydroxide and aqueous ammonia. In this case, mixing is performed so that the amount of alumina hydrate formed in the liquid does not exceed 5% by weight, the pH is 6 to 10, and the temperature is 20 to 10%.
The reaction is generally carried out at 0 ° C. Also,
A method of growing a crystal of alumina hydrate by alternately changing the pH to the acid and base side as described in JP-A-56-120508, as described in Japanese Patent Publication No. 4-33728. Alternatively, it can also be produced by mixing alumina hydrate obtained from an inorganic salt of aluminum with alumina obtained by the Bayer method, and rehydrating the alumina.

In the production of the recording material for ink-jet recording in the present invention, as a support to be used, for example, a polyester film, a resin-coated paper, a coated paper and the like are mainly used. The support is not particularly limited as long as the support can be provided with an ink absorbing layer such as a vapor-deposited film or a cloth.

The ink absorbing layer is provided on at least one side of the support, but is used for the purpose of preventing curling and the like.
It may be provided on both sides of the support.

In order to obtain an ink-jet recording material having a photographic paper-like glossiness and texture, which is one of the objects of the present invention, not only the composition of the ink absorbing layer but also the characteristics of the support are important. It is. It is preferable to use a polyester film or a resin-coated paper in order to obtain a photographic paper-like glossiness and texture of a photograph, and JIS-P
It is particularly preferred that the Hunter whiteness measured at -8123 is 65% or more.

Further, in order to have a photographic paper-like glossiness and texture, the hunter whiteness measured by JIS-P-8123 on the ink absorbing layer side of the ink jet recording material should be 65% or more. Are preferred, and JIS-Z-8
Preferably, the 60-degree specular gloss measured at 741 is 30% or more.

When a polyester film is used as the support for use in the present invention, the thickness thereof is not particularly limited, but is preferably about 10 to 200 μm from the viewpoint of handling properties and printer paper-passing suitability.

In the present invention, the polyester film refers to an aromatic dicarboxylic acid such as terephthalic acid, isophthalic acid, or naphthalenedicarboxylic acid, or an ester thereof, and a polyester film such as ethylene glycol, diethylene glycol, 1,4-butanediol, or neopentyl glycol. Polyester obtained by polycondensation with a polyhydric alcohol is a film, usually roll stretching, tenter stretching,
In many cases, orientation processing is performed by processing such as inflation stretching.

Specific examples of the polyester include polyethylene terephthalate, polyethylene butylene terephthalate, polyethylene-2,6-naphthalate and copolymers thereof with other components, but the present invention is not limited thereto. .

Examples of the method for increasing the whiteness of the polyester film include a method in which inorganic fine particles such as barium sulfate, titanium dioxide, calcium carbonate, silicon dioxide, aluminum oxide, kaolin, and talc are contained in the polyester film, and a method in which a white paint is applied to the surface. And the like.

In order to provide cushioning and concealing properties, a void-containing film containing a large number of voids inside the film, for example, a foamed polyester film can also be used.

When a resin-coated paper is used as the support in the present invention, the thickness is not particularly limited.
Those having a thickness of about 0 to 300 μm are preferred. Further, in order to obtain the texture of a photographic paper, it is preferably about 200 to 300 μm.

The base paper for the resin-coated paper is not particularly limited.
Generally used paper can be used, but preferably,
For example, a smooth base paper as used for a photographic support is preferable. As the pulp constituting the base paper, a natural pulp, a recycled pulp, a synthetic pulp, or the like is used alone or in combination of two or more. The base paper is blended with additives generally used in papermaking, such as a sizing agent, a paper strength enhancer, a filler, an antistatic agent, a fluorescent whitening agent, and a dye. Furthermore,
Surface sizing agent, surface paper strength agent, optical brightener, antistatic agent,
A dye, an anchoring agent and the like may be coated on the surface.

The base paper for resin-coated paper is preferably one having good surface smoothness such as compression by applying pressure with a calendar or the like during or after papermaking, and JIS-P-8.
Particularly preferred is a Beck having a smoothness of 200 seconds or more measured in 119. The basis weight is 30 to 250 g / m.
² is preferred.

The whiteness of base paper for resin-coated paper is determined according to JIS-
When the Hunter whiteness measured by P-8123 is 65% or more, the whiteness is high, and a high-quality recording material can be obtained. However, the whiteness required for the purpose is different, and unbleached pulp is used as a natural pulp. A brown base paper may be used in combination. Alternatively, base paper colored with a coloring agent such as a dye may be used.

As the coating resin for the resin-coated paper, a polyolefin resin is preferable, and a polyethylene resin is particularly preferable. Further, low density polyethylene, medium density polyethylene, high density polyethylene or a mixture thereof can be used. The low-density polyethylene referred to here has a density of 0.
It is 915 to 0.930 g / cm ³ and is usually manufactured by a high-pressure method. On the other hand, high-density polyethylene has a density of 0.950 g / cm ³ or more,
It is usually produced by a low pressure method or a medium pressure method. These polyethylene resins having various densities and melt flow rates can be used alone or in combination of two or more.

The structure of the resin layer of the resin-coated paper may be a single layer or two or more layers. Also in this case, the above polyolefin resins can be used alone or in combination of two or more. Further, the respective layers of the multilayer may have different compositions or the same composition.
As a method of forming a multilayer resin layer, any of a coextrusion coating method and a sequential coating method may be adopted.

On the other hand, the resin layer of the resin-coated paper can be formed by coating a latex having a film forming ability. For example, it can also be formed by coating a latex having a low minimum film formation temperature (MFT) on a base paper for resin-coated paper and then heating it to a temperature equal to or higher than the minimum film formation temperature.

The thickness of the coating resin layer of the resin-coated paper is not particularly limited, but it is generally coated to a thickness of 5 to 50 μm only on the surface or on both the front and back surfaces.

In the resin of the resin-coated paper, titanium dioxide,
White pigments such as zinc oxide, talc, calcium carbonate, etc., fatty acid amides such as stearamide, arachidic amide, fatty acid metal salts such as zinc stearate, calcium stearate, aluminum stearate, magnesium stearate, antioxidants, cobalt blue Blue pigments and dyes such as ultramarine, cecilian blue and phthalocyanine blue, and various additives such as magenta pigments and dyes such as cobalt violet, fast violet and manganese violet, fluorescent brighteners and ultraviolet absorbers are appropriately combined. Can be added.

The resin-coated paper used as a support in the present invention is produced by a so-called extrusion coating method in which a heated and melted polyolefin resin is cast on a running base paper. Further, in order to improve the adhesiveness between the resin and the base paper, it is preferable to perform an activation treatment such as a corona discharge treatment or a flame treatment on the base paper before coating the resin on the base paper. The surface (surface) of the support on which the ink absorbing layer is coated,
Depending on its use, it has a glossy surface, a matte surface, and the like, and a glossy surface is particularly preferably used. It is not always necessary to coat the back surface with a resin, but it is preferable to coat the resin from the viewpoint of curling prevention. The back surface is usually a matte surface, and the front surface or, if necessary, both the front and back surfaces can be subjected to an activation treatment such as a corona discharge treatment or a flame treatment.

The present invention also relates to a highly transparent ink-jet recording material that can be used as an OHP film. Not only the composition of the layer, but also the properties of the support are important. As for the light transmittance when used as an OHP film, the haze (cloudiness value) is closer to human feeling than the total light transmittance, and the haze (JIS-K-7105) according to JIS-K-7105 is used for the ink absorbing layer of the present invention. It is particularly preferable that the support is a transparent support having a haze value of 3.0 or less.

The haze of the ink jet recording material when used as an OHP film is as follows in an ink jet recording material provided with an ink absorbing layer on a support.
It is particularly preferable that the haze (haze value) of the recording material for inkjet according to JIS-K-7105 is 10.0 or less.

The haze (haze value) can be expressed by a ratio obtained by measuring the diffuse transmittance and the total light transmittance by using an integrating sphere light transmittance measuring device and expressing the ratio according to JIS-K-7.
105.

In a recording material such as an OHP film which requires light transmissivity, the thickness of the support to be used is not particularly limited, but it is preferably about 50 to 200 μm from the viewpoint of handling properties and printer paper passing suitability. preferable.

In the production of a recording material for ink-jet recording in the present invention, good coatability can be obtained in many cases without adding a surfactant, but in order to further improve coatability. Alternatively, a surfactant can be added for the purpose of adjusting the dot diameter when the ink adheres to the ink absorbing layer. The surfactant used is preferably a nonionic surfactant, but may be selected from anionic, cationic, nonionic and betaine types as necessary. It may be. One or more surfactants may be used in combination. The amount of the surfactant to be added is preferably 0.001 to 5 parts by weight, more preferably 0.01 to 3 parts by weight, based on 100 parts by weight of alumina hydrate constituting the ink absorbing layer in terms of solid content.

Further, in addition to the above-mentioned surfactants, the ink absorbing layer contains inorganic pigments, coloring dyes, coloring pigments, fixing agents for ink dyes, ultraviolet absorbers, antioxidants, pigment dispersants,
Various known additives such as an antifoaming agent, a leveling agent, a preservative, an optical brightener, a viscosity stabilizer, and a pH adjuster can also be added.

In order to improve the resolution of an image,
When agglomeration or the like does not occur when mixed with the dispersion of alumina hydrate, the ink absorbing layer contains a water repellent or sizing agent of a fluororesin type, a silicone resin type or an alkyl ketene dimer type. The resolution of an image can be improved by controlling the print dot diameter. As these fluorine resin-based, silicone resin-based or alkyl ketene dimer-based water repellents or sizing agents, commercially available ones can be used. Either of these solutions or aqueous emulsions can be used. The print dot diameter can be controlled by the amount of these water repellents added to the ink absorbing layer. The addition amount varies depending on each component, concentration and desired print dot diameter, but is usually 0.05 to 10% by weight, particularly preferably 0.1 to 5% by weight, based on the total solid content of the ink absorbing layer as an effective solid component. %.

The coating method of the ink absorbing layer coating liquid in the present invention includes, for example, a commonly used coating method such as a slide hopper method, a curtain method, an extrusion method, an air knife method, a roll coating method, and a rod bar coating method. A construction method is used.

The support in the present invention may be provided with an anchor layer for the purpose of improving the adhesion between the ink absorbing layer and the support. A hydrophilic binder such as gelatin, a solvent-soluble binder such as butyral, a latex, a curing agent, a pigment, a surfactant and the like can be appropriately added to the anchor layer.

The support in the present invention has an antistatic property,
For transportability, curl prevention, writing, gluing, etc.
Various back coat layers can be applied. An inorganic antistatic agent, an organic antistatic agent, a hydrophilic binder, a latex, a curing agent, a pigment, a lubricant, a surfactant and the like can be added to the back coat layer in an appropriate combination.

[0080]

EXAMPLES The present invention will be described below in detail with reference to examples, but the contents of the present invention are not limited to the examples.
In addition, "parts" means parts by weight.

(Production Example of Alumina Hydrate Dispersion) A production example of alumina hydrate used for the ink absorbing layer is shown below. All the raw materials used were commercial products and were used without further purification.

Production Example 1 800 parts of ion-exchanged water and 900 parts of isopropyl alcohol were charged into a 3 L reactor, 408 parts of aluminum isopropoxide were added, and the mixture was heated to 75.degree. Water 4 while distilling isopropyl alcohol
00 parts were added dropwise over 6 hours. After the isopropyl alcohol was distilled off, the temperature was raised to 95 ° C. and the mixture was aged for 24 hours. Thereafter, 24 parts of acetic acid was added, and the mixture was stirred at 75 ° C. for 12 hours, and then concentrated so that the total amount became 800 parts, to obtain a dispersion A of white alumina hydrate.

X-ray diffraction of xerogel obtained by drying this sol at room temperature showed a pseudo-boehmite structure. The average particle size measured by a transmission electron microscope was 10 nm, and the aspect ratio was 6. When the BET specific surface area, the average pore radius, and the pore volume were measured by the nitrogen adsorption / desorption method, each was 141 m.
^{2 /} g, 8.7 nm, 0.76 ml / g.

Production Example 2: Commercially available alumina sol (catalyst chemical, Cataloid AS-3) was dried with a spray drier (inlet temperature 200 ° C., outlet temperature 80 ° C.) to obtain xerogel. X-ray diffraction of this xerogel showed a pseudo-boehmite structure. Further, the average particle diameter was measured with a transmission electron microscope and found to be 10 nm. When the BET specific surface area, the average pore radius, and the pore volume were measured by the nitrogen adsorption / desorption method, each was 261 m
^{2 /} g, 6.7 nm, 0.77 ml / g.

25 parts of this xerogel was mixed with 75 parts of ion-exchanged water.
To obtain a white alumina hydrate dispersion B.

(Preparation Example of Coating Liquid) Preparation Example 1: Alumina hydrate dispersion A obtained in Production Example 1
100 parts of polyvinyl alcohol (Shin-Etsu Chemical, MA
-26) was added to 15 parts of a 10% aqueous solution to prepare a coating liquid A having an alumina hydrate content of 13%.

Preparation Example 2: To 100 parts of the alumina hydrate dispersion liquid B obtained in Production Example 2, 25 parts of a 10% aqueous solution of polyvinyl alcohol (Kuraray, PVA-635) was added.
A coating liquid B having an alumina hydrate content of 20% was prepared.

Preparation Example 3 A commercially available alumina sol (manufactured by Sato Research, Nanowhisker A-365, aspect ratio 4) was diluted with ion-exchanged water, and a 10% aqueous solution 25 of polyvinyl alcohol (manufactured by Kuraray, PVA-635) was added.
Was added to prepare a coating liquid C having an alumina hydrate content of 20%.

(Preparation of Inkjet Recording Material) The following is an example of producing an inkjet recording material according to the present invention, but the present invention is not limited thereto.

Example 1 A coating solution A prepared in Preparation Example 1 was applied to a white polyester film (manufactured by ICI, Melinex 339, thickness 9).
(7 μm) so that the coating amount of the coating liquid was 200 g / m ² . Until the alumina hydrate content of the coating solution applied on the support exceeded 25% by weight, the coating surface was dried using an infrared heater in a state in which substantially no air was applied to the coating surface. Next, hot air at 120 ° C. was sprayed onto the coated surface at a rate of 15 m / s to produce an inkjet recording material. No crack was observed in the ink absorbing layer of the obtained ink jet recording material.

Further, the 60-degree specular gloss was measured according to the method of JIS-Z-8741, and it was 88%. In order to have a photographic paper-like texture of a photograph, the 60-degree specular gloss is preferably 70% or more.

Example 2 A coating liquid B prepared in Preparation Example 2 was applied to a transparent polyester film (manufactured by ICI, Melinex 705, thickness 1).
(00 μm) so that the coating amount of the coating solution was 200 g / m ² . A hot air of 120 ° C. is blown from the back of the support until the coating solution applied on the support has an alumina hydrate content of more than 25% by weight, and substantially no wind is blown on the coating side. And dried. Next, hot air of 120 ° C was applied at 15 m /
s was sprayed onto the coated surface to produce an inkjet recording material. No crack was observed in the ink absorbing layer of the obtained ink jet recording material.

The haze (haze value) measured according to the method of JIS-K-7105 was 6.2. O
For use as an HP film, the haze is 1
It is particularly preferred that it is 0.0 or less.

Example 3 A coating liquid B prepared in Preparation Example 2 was applied to a transparent polyester film (Meinex 705, manufactured by ICI, thickness: 1).
(00 μm) so that the coating amount of the coating solution was 200 g / m ² . Until the alumina hydrate content of the coating liquid applied on the support exceeds 25% by weight, a hot roll is pressed against the back surface of the support at 120 ° C., and substantially no air is applied to the coated side. And dried. Next, hot air of 120 ° C is applied for 15 minutes.
m / s was sprayed onto the coated surface to produce an inkjet recording material. No crack was observed in the ink absorbing layer of the obtained ink jet recording material. Also,
When the haze (cloudiness value) was measured according to the method of JIS-K-7105, it was 6.0.

Example 4 The coating liquid B prepared in Preparation Example 2 was applied to a transparent polyester film (Meinex 705, manufactured by ICI, Inc., thickness 1).
(00 μm) so that the coating amount of the coating solution was 200 g / m ² . Hot air of 120 ° C. is blown onto the wall of the dryer, and the inside of the dryer is kept at 120 ° C. until the alumina hydrate content of the coating liquid applied on the support exceeds 25% by weight. Was dried in a substantially airless state. Next, hot air at 120 ° C. was sprayed onto the coated surface at a rate of 15 m / s to produce a recording material for inkjet. No crack was observed in the ink absorbing layer of the obtained ink jet recording material. Also, JIS-K-7105
When the haze (haze value) was measured according to the method described above, it was 6.0.
Met.

Example 5 A coating liquid C prepared in Preparation Example 3 was applied to a white polyester film (Meinex 339, manufactured by ICI, thickness 9).
(7 μm) so that the coating amount of the coating liquid was 200 g / m ² . Until the alumina hydrate content of the coating solution applied on the support exceeded 25% by weight, the coating surface was dried using an infrared heater in a state in which substantially no air was applied to the coating surface. Next, hot air at 120 ° C. was sprayed onto the coated surface at a rate of 15 m / s to produce an inkjet recording material. No crack was observed in the ink absorbing layer of the obtained ink jet recording material. Also, JIS-Z-8741
When the 60-degree specular gloss was measured according to the method described above, 92%
Met.

Comparative Example 1 The coating liquid B prepared in Preparation Example 2 was applied to a transparent polyester film (Meinex 705, manufactured by ICI, thickness: 1).
(00 μm) so that the coating amount of the coating solution was 200 g / m ² . Next, hot air at 120 ° C. was sprayed onto the coating surface side at a rate of 15 m / s to prepare a recording material for inkjet. Cracks occurred on almost the entire surface of the ink absorbing layer of the obtained ink jet recording material. Also, JIS-
When the haze (cloudiness value) was measured according to the method of K-7105, it was 26.4.

Comparative Example 2 A coating liquid B prepared in Preparation Example 2 was applied to a white polyester film (Meinex 339, thickness 9 cm, manufactured by ICI).
(7 μm) so that the coating amount of the coating liquid was 200 g / m ² . Next, hot air at 120 ° C. was sprayed onto the coating surface side at a rate of 15 m / s to prepare a recording material for inkjet.
Cracks occurred on almost the entire surface of the ink absorbing layer of the obtained ink jet recording material. Also, JI
The specular gloss at 60 degrees measured according to the method of SZ-8741 was 58%.

(Printing Evaluation) Printing was performed on the ink jet recording materials obtained in Examples 1 to 5 using a full color ink jet printer BJC-610J manufactured by Canon. As a result, all of the ink jet recording materials had no unevenness or the like in the printed portions, and had good image quality.

[0100]

As is apparent from the examples, in the method for producing an ink jet recording material having an ink absorbing layer containing alumina hydrate on a support, cracking of the ink absorbing layer during drying is suppressed. It is possible to provide a method for manufacturing a recording material for ink-jet recording.

Claims (4)

[Claims] 1. A method for producing a recording material for ink-jet recording, wherein an ink absorbing layer containing alumina hydrate is provided on a support, wherein a coating liquid containing alumina hydrate is applied on the support. An ink-absorbing layer formed by drying the coating surface without substantially blowing air until the concentration of the coating liquid applied on the support exceeds 25% by weight; A method for manufacturing a recording material. 2. The method according to claim 1, wherein the concentration of the coating liquid applied on the support is 25.
2. The method according to claim 1, wherein drying is performed using a heat light source until the amount exceeds the weight percentage. 3. The concentration of a coating liquid applied on a support is 25.
2. The method for producing a recording material for ink jet recording according to claim 1, wherein hot air is applied to the surface of the support opposite to the surface on which the coating liquid has been applied until the amount exceeds the weight%. 4. The concentration of a coating solution applied on a support is 25.
2. The method according to claim 1, wherein a heating medium is applied to the surface of the support opposite to the surface on which the coating liquid has been applied until the amount exceeds the weight%, and the support is dried.